[Mesa-dev] [PATCH 1/6] nir: Convert ineg(b2i(a)) to a if it's a boolean.

[Erik Faye-Lund]

On Wed, Aug 10, 2016 at 5:40 PM, Jason Ekstrand <jason at jlekstrand.net> wrote:
> On Aug 10, 2016 1:00 AM, "Erik Faye-Lund" <kusmabite at gmail.com> wrote:
>>
>> On Wed, Aug 10, 2016 at 4:30 AM, Kenneth Graunke <kenneth at whitecape.org>
>> wrote:
>> > On Haswell (GL 3.3):
>> >
>> > total instructions in shared programs: 6211678 -> 6211584 (-0.00%)
>> > instructions in affected programs: 18968 -> 18874 (-0.50%)
>> > helped: 62
>> > HURT: 0
>> > LOST:   0
>> > GAINED: 4
>> >
>> > On Broadwell (GL 4.4):
>> >
>> > total instructions in shared programs: 11638930 -> 11638181 (-0.01%)
>> > instructions in affected programs: 84768 -> 84019 (-0.88%)
>> > helped: 505
>> > HURT: 45
>> >
>> > Signed-off-by: Kenneth Graunke <kenneth at whitecape.org>
>> > ---
>> >  src/compiler/nir/nir_opt_algebraic.py | 1 +
>> >  1 file changed, 1 insertion(+)
>> >
>> > diff --git a/src/compiler/nir/nir_opt_algebraic.py
>> > b/src/compiler/nir/nir_opt_algebraic.py
>> > index 0f0896b..1cf614c 100644
>> > --- a/src/compiler/nir/nir_opt_algebraic.py
>> > +++ b/src/compiler/nir/nir_opt_algebraic.py
>> > @@ -180,6 +180,7 @@ optimizations = [
>> >     (('fmul', ('b2f', a), ('b2f', b)), ('b2f', ('iand', a, b))),
>> >     (('fsat', ('fadd', ('b2f', a), ('b2f', b))), ('b2f', ('ior', a,
>> > b))),
>> >     (('iand', 'a at bool', 1.0), ('b2f', a)),
>> > +   (('ineg', ('b2i', 'a at bool')), a),
>> >     (('flt', ('fneg', ('b2f', a)), 0), a), # Generated by TGSI KILL_IF.
>> >     (('flt', ('fsub', 0.0, ('b2f', a)), 0), a), # Generated by TGSI
>> > KILL_IF.
>> >     # Comparison with the same args.  Note that these are not done for
>>
>> Are you sure this shouldn't be conditional? This being an improvement
>> sounds like an intel-ism, and not something that applies to most
>> hardware...
>
> Why? You're replacing two instructions with zero. That should help everyone.

My bad, I somehow read this as something entirely different. Sorry for
the noise, looks good to me.